The present invention relates to an improved integrated circuit package including a semiconductor chip, a metal heat sink and an electrically-insulating adhesive bonding the chip to the metal heat sink.
Modern integrated circuit packages oftentimes include semiconductor dies or chips bonded to a metal heat sink. Typically, the metal heat sink is carried on or by an electrically insulating carrier made from an epoxy resin or other plastic. In order to secure the chip in place, a glob of another epoxy or other resin is used to encapsulate the chip as well as any metal wires present for electrically connecting the chip to leads on the carrier.
In order to securely bond the chip to the metal heat sink, an electrically-insulating adhesive is used. Since the function of the metal heat sink is to absorb heat generated in the chip, this adhesive must exhibit a high thermal conductivity. In addition, this adhesive must also exhibit a high bond strength to the material forming the chip, most typically silicon, as well as a high bond strength to the metal forming the metal heat sink.
As modern chips become larger and larger, both in terms of size as well as power consumed, the stresses put on the chip/heat sink bond become greater and greater. As a result delamination of the chip from the heat sink is a growing problem in the industry today.
Accordingly, there is a need for a new bonding system for bonding a semiconductor chip to a metal heat sink which can accommodate the high stresses and heat involved in modern integrated circuit package designs and yet is still simple and inexpensive to carry out.